Color vision in Attention-Deficit/Hyperactivity Disorder: A pilot visual evoked potential study

Background: Individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) are reported to manifest visual problems (including ophthalmological and color perception problems, particularly for blue-yellow stimuli), but findings are inconsistent. Accordingly, this study investigated visual function and color perception in adolescents with ADHD using VEP. Method: Participants were 31 adolescents (aged 13-18); 16 with a confirmed diagnosis of ADHD, and 15 healthy peers, matched for age, gender, and IQ. All underwent ophthalmological exam, color vision testing (Mollon-Reffin Minimalist Colour Vision Test), as well as electrophysiological testing (color Visual Evoked Potentials; cVEP) which measured the latency and amplitude of the neural P1 response to chromatic stimuli (Blue-Yellow, Red-Green). Result: No group differences were found in clinical measure of color perception or opthalmological exam. However, significantly larger P1 amplitude was found for blue and yellow stimuli, but not red/green stimuli, in the ADHD group compared to controls. Discussion: Larger amplitude in the P1 component for blue-yellow in ADHD group compared to control group may account for no difference in colour perception task. Perhaps activating more resources in early sensory processing (P1) compensated for any underlying problems including compromised retinal input of s-cones due to hypo-dopaminergic tone.